1. Field of the Invention
The present invention relates to a socket for mounting a semiconductor laser and the like employed in devices for optical transmission, devices for optical LAN (Local Area Network) and the like, on a substrate.
2. Description of the Prior Art
A semiconductor laser is used as a light source in a compact disk player, a laser printer, or the like. As shown in FIG. 8, a package 1 of a round type semiconductor laser normally has its current introducing pin, an output lead pin 3 and so on projected in the direction horizontal to the direction of emission of the laser chip 2. This structure is for convenience of connection to an optical system mainly comprising a lens, a prism and the like. FIG. 9 shows the package 1 of the semiconductor laser actually applied on a circuit board as a fiber output for optical transmission. The semiconductor laser package 1 is fixed in a direction vertical to the surface of the circuit board 4 with tip end portions of the lead pins 3 passing through the circuit board 4 to be soldered 5 on the rear surface of the board 4. A fiber cable 7 is connected to an emitting side of the semiconductor package 1 through a connector 6 coaxially with the laser emitting axis. Therefore, mounted in this manner, the fiber cable 7 is drawn out in the direction vertical to the surface of the circuit board 4.
However, the above described mounting method is inconvenient when devices for optical transmission and the like should be made compact. More specifically, when a number of circuit boards 4 should be stacked on each other to make the device compact, the fiber cable 7 becomes an obstruction in stacking boards since it is drawn out in the direction of stacking. In order to solve this problem, the fiber cable 7 should be drawn out in the direction parallel to the surface of the board 4. FIG. 10 shows a mounting method in which lead pins 3 of the semiconductor laser package 1 are bent so that the fiber cable 7 is drawn out in the direction parallel to the surface of the substrate 4. However, this method has disadvantages that the bent portions of the lead pins 3 become physically weak, and that there is no reproductivity, that is, when a semiconductor laser should be replaced, it cannot be attached on the same portion as that before the replacement.
The above described problems are derived from the fact that the package 1 of the semiconductor laser is directly mounted on the circuit board.